A NULL pointer dereference bug has been identified in the Linux kernel due to a data race. This issue occurs when the `fscache cookie state machine()` function is slow and still running while another process invokes `fscache unuse cookie()`, leading to a `fscache cookie lru do one()` call that sets the `FSCACHE COOKIE DO LRU DISCARD` flag. This flag is then picked up by `fscache cookie state machine()`, which withdraws the cookie via `cachefiles withdraw cookie()` and clears `cookie->cache priv`. At the same time, another process may invoke `cachefiles prepare write()`, finding a NULL pointer in the code line `struct cachefiles object *object = cachefiles cres object(cres)`, causing a crash. The `n accesses` counter is non-zero during `cachefiles prepare write()` (via `fscache begin operation()`), and the cookie must not be withdrawn until this counter drops to zero. The counter is checked by `fscache cookie state machine()` before switching to certain states, but not for `FSCACHE COOKIE STATE LRU DISCARDING`. This patch adds the missing check, ensuring that with a non-zero access counter, the function returns and the next `fscache end cookie access()` call will queue another `fscache cookie state machine()` call to handle the still-pending `FSCACHE COOKIE DO LRU DISCARD`.